The present invention relates to a motor vehicle having front wheels which are steerable via a steering wheel and rear wheels which are automatically steerable via an actuator.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
When driving in reverse, a driver often has difficulties to handle or control a motor vehicle which only has a steerable front axle, because this situation essentially corresponds to rear wheel steering when driving in reverse. This causes an unstable driving behavior for the driver, because the motor vehicle immediately travels sideways for even a small excursion of the front wheels. This frequently results in a pendulum motion which it is difficult to collect by counter-steering. The difficulty of driving in reverse is mostly caused by the widely pivoting part of the vehicle and the fact that the driver is typically unable to anticipate the path of the rear wheels based on the excursion of the front wheels.
In some conventional application, the rear wheels are steered based on a characteristic curve field, wherein in a steering angle interval between 0° and a predetermined limit angle, the rear wheels are first adjusted to increase with increasing steering angle from a zero position in the same direction until reaching a maximum excursion and are adjusted, after having reached the limit angle, to decrease until reaching the zero position, and are adjusted in the steering angle interval between the predetermined limit angle and the maximum steering angle to again increase in the opposite direction until the maximum excursion is reached.
The proportionality factor which is stored in the employed characteristic curve field and which indicates the position of the rear wheels in relation to the front wheels while steering from the left limit stop to the right limit stop, or vice versa, includes a transition from a position of the rear wheels in relation to the front wheels from an opposite direction to an identical direction and then again to an opposite direction. In this maneuver, the rear wheels tend to “flutter”, in particular at a low constant speed. The subjective driving experience is not satisfactory.
It would therefore be desirable and advantageous to obviate prior art shortcomings and to provide a motor vehicle with an improved driving behavior when driving in reverse.